The present invention relates to a rolling head for applying sealing caps on bottles of wine, liquor, and beverages in general.
It is known that sealing caps can be made of heat-shrinkable or moldable material, for example polymeric material with fillers constituted by metallic powders, or metal or ductile metal alloys.
The present invention relates to a rolling head for applying caps of the second type, which are made to adhere perfectly to the neck of the bottle, coupling to any raised portions or undercut collars, by means of a plurality of presser rollers of said head, which roll on the cap and apply thereto a pressure directed radially, while the head moves along the neck of the bottle in order to subject the entire extension of the cap to the action of the rollers.
In known rotating rolling heads of the specified type, the presser rollers are located at the ends of respective oscillating shafts that are arranged in a bundle along a hollow rotating body of the head adapted to receive the neck of the bottle and are pivoted to the upper end of said rotating body.
Two or more elastomeric rings cooperate with the bundle of oscillating shafts and elastically tighten them, generating a corresponding elastic radial force on the presser rollers.
The pressure the rollers apply to the cap can be changed by placing the rings at different levels and/or by mutually spacing them in various manners.
Said known rolling heads have several drawbacks; the main one resides in their considerable sensitivity to the action of centrifugal force.
In particular, due to the significant mass of the supporting shafts of the presser rollers, said bundle of shafts, under the action of centrifugal force, tends to open out, significantly reducing the action of the elastomeric rings, with a corresponding significant reduction in the action applied by the presser rollers on the cap, which accordingly does not adhere correctly to the neck of the bottle. It is therefore necessary to significantly limit the rotation rate of the head, correspondingly reducing its efficiency in terms of caps applied in the time unit.
Another drawback of said known rolling heads is the difficulty in performing, and maintaining in the course of time, a correct adjustment of the force applied by the elastomeric rings on the presser rollers, and therefore the corresponding difficulty in adapting the head to the processing of caps of different kinds and consistencies and/or in ensuring a constant-quality and high-standard production.
A presser stem is also associated with said rolling heads and slides axially, under the actuation of elastic means, within a sleeve that supports the rotating body adapted to receive the bottle and having the dual function of keeping in place the cap during rolling and of helping to expel the bottle after rolling. In known rolling heads, this stem is subjected to the action of a plurality of springs according to an arrangement structurally complicated, expensive, and difficult to adjust, which entails additional drawbacks, both from the functional point of view and from the point of view of the complexity of the adjustment operations.